On Friday, Prime Minister Tony Abbott declared there would be no more taxpayer assistance for Holden and called on it to reveal its plans.

Mr Truss says he is concerned about the situation.

"The comments made this morning by Mr Devereux, the general manager, that no decision has been made at this point just adds to the uncertainty," he told Parliament.

"What we need is, and what this Government has said, is a clear commitment that we want General Motors to be active in Australia.

"The statements today include no clear commitment to stay manufacturing in this country and yet it was only two years ago when Holden had said it had achieved sustainable profitability in Australia.

"And now it has not ruled our abandoning manufacturing in this country."

He says General Motors Holden should make an immediate statement "clarifying their intentions".

"They owe this to the workers at General Motors," he said.

"Let us not go into a Christmas period without them making a clear commitment to manufacturing in this country."

But Industry Minister Ian Macfarlane has responded to Labor questions about the issue by emphasising that the Government's final response on the issue is not due until the Productivity Commission hands down its findings in March.

Holden boss fronts Productivity Commission

Holden currently employs 3,500 people in plants in Victoria and Adelaide and its operations support the employment of workers in various components companies.

Mr Devereux told the Productivity Commission that the cost of losing the car manufacturing industry would dwarf the cost of keeping it, and warned of the disastrous effect Holden's withdrawal would have on the economy.

The economic benefit of us making things is $33 billion to the Australian economy. That's 18 times the assistance we receive.

Holden general manager Mike Devereux

"The economic benefit of us making things is $33 billion to the Australian economy," he said.

"That's 18 times the assistance we receive."

Mr Devereux said every job in the automotive industry created two to three others in the wider economy.

He told the commission, whose report is due out early next year, that it costs the company $3,750 per car, or around $300 million extra per year, to manufacture cars in Australia.

However, he said Holden does not expect the Federal Government to "close that gap".